How to detail my sword texture?
The best way to go from here is to find some images of swords that you can refer to. From what I know, most swords would be kept well polished and mostly scratch free. If you're going a bit more stylized like you would find in a game, then some scratches on the edge from cutting things would be one of the first things to add.

Before you continue texturing though, I would recommend working on your lighting. One of the reasons the second image "pops" a bit more is due to the colored lights. The main light appears to be a warm off-white, and the second light is coming in from the left and adds a bit of blue to certain surfaces. I would suggest looking at some lighting videos or tips online to help you get started there. Lighting can often be what makes or breaks an image.

The final thing to do would be to add variations in the roughness, spectacular, and normal of your material. Once you have your final diffuse texture you can either use the compositor to convert the image to be able to control each aspect, or some other program to generate the maps from the diffuse texture.